There are already known a lot of patent literatures relating to deodorant compositions which may mainly be classified into the four species mentioned below.
(i) Deodorizer which appeals to human's sense, i.e. odor feeling. PA1 (ii) deodorizer which exhibits deodorization activity due to physical adsorption action. PA1 (iii) deodorizer which exerts deodorization activity by the use of microorganism. PA1 (iv) deodorizer which shows deodorization activity due to the mechanism of chemical reaction. PA1 (i) Natural gel forming substances: agar-agar, gelatin, egg white, starch, caragenane, sodium alginate and the like. PA1 (ii) Synthetic gel forming substances: polyvinyl alcohol, carboxymethylcellulose, sodium polyacrylate, polyacrylamide and the like.
More specifically, the deodorizer of the first type is the one which utilizes a masking method by fragrant materials. According to the nature of bad odors, however, this method has a drawback that unpleasant bad odors may sometimes be promoted by the fragrant materials employed. Moreover, the deodorizer of the second type contains an active carbon as main ingredient and so has disadvantages that it is poor to moisture content and that it may also adsorb pleasant smells to human beings. Furthermore, the deodorizer of the third type suffers from drawbacks that it has a weak activity on immediate deodorization effect and is often difficult to control under appropriate conditions. Whereas, the deodorizer of the fourth type has remarkable advantages that is takes fast-acting deodorization effect, is very easy to handle and safe by the appropriate choice of active reagent to be used and may cause the desired deodorization efficiency to be ensured.
This invention provides a deodorant composition in the form of gel into which a deodorizer acting on malodors through chemical reactions is incorporated. The sources generating foul-smelling gases are in refrigerators, toilet area such as that in households, motor vehicles, buses or aircrafts and in automobiles, which may in each case form enclosed areas very poor in diffusion efficiency of foul-smelling gases. It is desirable to spray as avoidably as possible the enclosed area with a deodorizing reagent. As an alternative to spraying the deodorizing reagent, the use of either active carbon of fragrant materials is most commonly conducted. The active carbon, while of course having a deodorization capacity, suffers from disadvantages. In addition to its degradation due to moisture content, it often shows a reduced deodorization activity when foul-smelling gases are actually generated in the enclosed area, because it may randomly adsorb not only malodors but also sweet smells exerted from fragrant reagents and bad-odorless smell. Whereas, a deodorant composition in the form of gel and containing therein a deodorizer acting on malodors through chemical reactions has advantages that it reacts selectively with only bad odors dependent upon the nature of deodorizing reagents contained therein and that the time of exchanging the deodorant composition can be determined when examined visually, because the water content contained in the gel evaporates with the lapse of time and the gel is thereby reduced in size. Moreover, it is also possible to use a deodorization method wherein a liquid deodorizer held in a container is positioned at the sources generating foul-smelling gases to deodorize said smells, but this method suffers from a drawback that the liquid deodorizer readily flows out of the container and with which peripheral circumstances are contaminated when the container is subjected to vibration or falling down thereof. When the liquid deodorizer is gelled to make a gel, such problems as mentioned above can be totally eliminated. Furthermore, there are some commercially available gel-typed deodorant compositions at the present time, but these commercial products are poor in deodorization activity (please refer to Example 3 below).
We, the present inventors, have made extensive researches in an attempt to seek for such deodorant composition as dissolving above problems, and we have now found that there may be obtained a novel, chemically reacting deodorant composition in the form of gel which comprises a gel forming material, a gelling agent, a chemically reacting deodorizer containing as active ingredients a betaine compound an alcoholic amine compound and an aldehyde compound, and water in specific proportions.